Telephone system and apparatus therefor.



no. 673,039. Pafntd Apr. 3o, |901.

. A. T. n. manson.

TELEPHUNE SYSTEM AND APPARATUS THEREFOB.

(.ppumionmed occ. s, 1899.)

(No Ilodal.)

6 Shoots-Sheet l.

TH: nonms Evans cc. miam-uma. wumo'row nv c, 1

M. 673.039. ranma Apr. 3o, 19m. A. T. n. manson.

TELEPHUNE SYSTEM AND APPARATUS THEREFOB.

(Application Med Qct. 9, 1899.)

m: Npnms PErzRs co.. PHofaLn'no., wAsHmmou: D. c.

No. 673,639. 4 Patented Apr. 30, I90l.

` A. T. M. THOMSON. l

TELEPHONE SYSTEM AND APPARATUS THEREFOB.

' (Appumiqn med ore. 9, 189s.) (Ilo Modal.) l 6 Sheets-Sheet 3.

No. 673,039. Patented Apr. 30, 190|.

A. T. I. THOMSUN. TELEPHONE SYSTEM AND APPARATUS THEBEFUR.)

l(lpplimtiml led Oct. 9, 1899.)

6 Shoots-Shoot 4.

No.' 673,039. Patented Apr. 30,1901.

A. T. n. Thomson.

TELEPHONE SYSTEU AND APPARATUS THEREFOR.

(Application 'Bled Oct. 9, 1890.) (lo INM.)- 6 Sheets-Sheet B.

No. 673,039. Patent Apr. 3u, mul.

A. T. n. THousou. TELEPHONE SYSTEH AND APPARATUS THEREFUR.

v (Aimnmim and oeck n, 1an.)

(No Iodel.)

El l 15u/mlm:

Tn: Nonnfs PETERS ca. vuoraumo.. WASHINGTON. D. c.

UNITED STATESi PATENT OFFICE.

ARTHUR`THOMASMILNOR rFHOMSON, OF EAST DULWICH, ENGLAND.

TELEPHONESYSTEM ANfo APPARATUS THEREFOR.

SPECIFICATION forming part of Letters Patent No. 673,039, dated April30, 1901.

Application filed October 9. 1899. Serial No. 733.069. (No model.)

full, clear, and exact description of the in- Vention, such as willenable others skilled in the art to which it appertains to make and usethe same. Y

This invention relates to improvements in telephone systems and inapparatus therefor.

The invention is more especially designed With a View to simplify,facilitate, expedite, and lessen the cost of working of complextelephone connections such as are required for an eiticient service inlarge towns-that is to say, wherever' the number of subscribers or usersis very large, and consequently the system as a whole very busy; but ofcourse it is applicable to any lesser demands.

Themain objects of the invention are, first, to do away with the verbalintercommunication between the subscribers or users and the operators atthe exchange now necessary in order for one subscriber to be put intocomm unication with another or one exchange with another, as thecasegmay be, and thus avoid all the attendant inconveniences andsubstitute therefor what maybe called a secret service, because theoperators at the exchange have no means by which to overhear theconversation between two users, and, second, to do away entirely withthe present multiple switchboard and so simplify and. cheapen the outfitand expedite the operating at the exchange and cost of operating andmaintaining the system and service.

The invention consists, then, in certain apparatus and in the group orcombination of these apparatus comprising signaling, printing, andindicating devices and in the coinbination of this group o f apparatuswith ordinary or well-known telephonie instruments and connections toform a complete novel telephonie system.

Before describing the new group of apparatus itself it may be well tomention here, in order to render what follows the more intelligible,that part ot' this apparatus is located at the subscribers end ot theline, and is substituted for the present ringing-up orsignaltransmitting apparatus of an ordinary telephone set, andypart atthe exchange, that the operators at the exchange in this system are notprovided with telephone receivers and transmitters, and that the sourceof the electric or magnetic current employed for automaticallysignaling, indicating, recording, and clearing the connections issituated preferably at the exchange; but as in some cases it may be moredesirable to locate it at the user-s end of the line it is to beunderstood that I do not bind myself in this respect.

I will now proceed to describe my invention in detail, reference beinghad to the accompanying drawings, illustrating same, and in which-Figure 1 is a rear elevation of one form of the. indicator-switch,telephone apparatus, and connections at the subscribers or users end ofthe line. Figs. 2, 3, and-tare respectively a cross-section and side andfront elevations ot' the gravity latent switch, Fig. 1. Fig. 5 is a planof the printer used to print the names of exchanges and shows how it isconnected with the special switch. Fig. 6 is an elevation of the specialswitch at the exchange consisting ot' an oscillatory springjack andplug, the latter being shown insei-ted and in the position for operatinga call. lts connections with the exchange-printer, line-wires, andspecial indicator are also shown. Fig. 7 is the specialoscillatoryindicator which distinguishes a call on the local exchange from one fora distant' exchange, its connections with the jack at theswitchingboard, the special switch, the exchangeprinter, and theline-wires. Fig. 8 is va section of the exchange-printer, taken on theline 8 S of Fig. 5. Fig. 9 is a diagrammatic plan of the latent switch LS, the engaged or busy signal E S, the exchange-printer- E P,

the special jack-switch J S, the special indicater S I, and theirconnections. 1l are respectively an end view and front elevation of thespecial indicatorS I. Fig. l2 is a diagrammatic plan of the numericalprinter N P, clearing-relays C R, visualsignals V S, and theirconnections. Fig. 13 is a diagram of the entire system, showing theapparatus and connections necessary for a complete call Figs. 10 and.

from one subscriber to another, the gravity form of latent switch beingemployed, L S being the latent switches, E S the engaged signals, C Bthe call-bells, E P the exchangeprinter, N P the numerical printer, J Sthe special jack-switches, S I the special compound indicator, C R theclearing-relays, and V S the visual signals.

Latent swt'tch- Gravity type- The instrument or apparatus substitutedfor the usual telephone-call set or outiit at the subscribers office orend of the line is an indicator latent switch, and is hereinafter forbrevity referred to as the latent switch. This switch is shown in detailin Figs. 1, 2, 3, and 4 and is composed substantially as follows: On abase or foundation plate 1 is mounted in a bracket 2 an electromagnet 3,one terminal of which is electrically connected by means of the wire 3',insulated make-andbreak contact 32'33, and line-wire L', or, on theother hand, by the wire 3, insulated makeand-break contact 34 35, andline-wire L2 with aspecial switch situated at the exchange, preferablynear the originating operator-that is, the operator who first receivesthe call. This special switch will be described in its turn later on;but I may here brieliy remark that it is preferably of the spring-jackand plug type and is shown in detail at J S in Fig. 6 and indiagrammatic form in combination in other figures, the line-wires L L2terminating at the exchange in the plug J P of the said switch. Theother terminal of the magnet 3 is connected, as indicated, by the plateE to earth. Mounted also upon the base-plate 1 at the back thereof areiive plates 4, 5, 6, 7, and 8, bearing a number of raised contacts,respectively 4', 5, 6', 7', and 8, in or upon their exposed or rearsurface, the said contacts being advantageously formed as ridges or ribsproduced by merely iiutiug, grooving, or corrugating the plates, but maybe produced in any other suitable way. These plates are mounted upon thefoundation-plate in such a manner as to be slidable thereon transverselyin a substantially horizontal direction, the mechanism by which they aremoved being advantageously formed, as shown ,consisting of a spindle 9,rotatably mounted in the base-plate 1, a toothed pinion 10, fast on therear end of said spindle, a rack 11, formed in or secured fast to thefront face of the movable contactplates and always in engagement withsaid pinion, and a milled thumb-nut 12, screwed fast on the outerorfrontend of the spindle 9, so that turning this nut in either directioncauses a corresljronding sliding movement of the contact-plates byreason of the pinion 10 engaging in the teeth of the rack 11, which itmoves, the contact-plates sliding between the foundation-plate 1 andguides 13.

The contacts on the plate 4 represent the various exchanges inthe townor city area and also, where necessary, special services, such as trun kor long-distance calls-1.l1atis, to exchanges in towns or cities outsidethe area of the others-telegraph-oice, postofiice, special-messengerservice, and also certain special officials in such offices, such asclerk in charge, &c. The contacts on plates 5, 6, 7, and Srepresent,respectively, the thousand, hundreds, tens, and units of the subscribersor users numbers. The movable plates are all in electrical connectionwith the metallic foundation-plate 1, wires 43 serving to emphasize thisconnection.

It will be observed in Fig. 1 that the plates in question are cut olfobliquely at their outer ends, terminating at their upper edges in apoint, while the edge of the foundationplate is cut squarely or at rightangles to the top and bottom edges of the movable plates. The object ofthis is to enable the exposure beyond the edge of the foundationplate ofa single one or any number of the contacts at will by simply turning thethumbnut in the outward direction, so as to advance the con tact-plateto the desired extent. In order to inform the user from the outside ofthe apparatus as to how much to advance the plates so as to expose theright number of contacts to give a call correctly, disk wheels or dials14, having notches 15 in their peripheries, and figures, letters, orother signs or combinations of figures, letters, or signs on their outerfaces, preferably near to the periphery, may be iixed on the spindles 9ontside in front of the foundation-plate 1 between it and the thumb-nutsor knobs 12. The said numerals or other characters or signs correspondto the number ot' contacts exposed, and as these contacts, as abovestated, represent. the different exchanges,spe cial services, and ordersof numerals constituting the subscribers numbers the user by simplyturning the knobs or thumb-nuts 12 can set these dials to any exchangeand number on that exchange desired.

In the construction shown in the drawings the spring 16 acts inconjunction with the notches 15 in the periphery of thedials, each ofthe notches being exactly in alinement with the numeral, character, orsign on the dial, and thus serves as a guide or pointer by which theadjustment may be effected with facility and accuracy. The adjustmentmay, however, be elfected in several other ways, and I do not,therefore, confine myself to any particular device in this respect. Forexample, the disks 14 may not be fast on the spindle 9, but supportedaround it, and the spindle may carry an index or radial pointer whichcan be turned to any of the positions by the thumb-nut 12. Or, again,the dial may be fast on the spindle, but entirely inclosed or covered upwith the exception of one little window in a cover-plate, through whichone of the numerals, characters, or words may be exposed at a time.

The contact-linger which works in conjunction with the contact-plates 4,5, 6, 7, and 8 is of course electrically insulated from them and iscarried by a movable earth-connected ITO block 17. This block is mountedupon a supportin such a manner as to be capable of moving transverselyover or past all the contacts on the contact-plates should all thesecontacts be exposed in its path, its contact-finger 30 brushing acrossthe contacts as it travels. As a means of support for the block inquestion I prefer to mount, it upon a screw-spindle 18, having,preferably,a helical thread, the block having acorrespondingly-screwthreaded hole through it. The block is threaded onthe spindle and the latter supported in end bearings, so as to be freeto turn. This spindle 18, then, is supported at each end in bearings insucha manner as to be capable of being freely rotated about its axis,

i but incapable of any longitudinal movement.

This spindle is rotated in one direction by hand by means of the toothedsector-lever 25, (best seen in Fig. 2,) which is pivoted to the frame atO and engages with apinion 19, fast on a toothed wheel 20, which engageswith teeth 18t on the spindle 18, the movement being preferablyregulated'by means of a fan 28, through the intervention of a train ofwheels consisting of the pinion 29, fast on the fan-spindle, the toothedwheel 20, in engagement with a pinion 21, fast on a toothed wheel 22,which engages with a pinion 23, fast on a toothed wheel 24, which is inengagement with the pinion 29 on the fan.

The armature 26 of the magnet 3 is pivoted at 27, and the extremityremote from the magnet is provided with a pin 27', which normally-thatis, when the magnet is denergized,and therefore not holding itsarmatureis in engagement with or resting against a notch or stop-toothformed in or upon the periphery of a plain wheel or disk 90, mountedfast on one of the spindles of the winding-up train of wheels,preferably the one bearing the toothed wheel 20. The coperation of thispin and tooth or notch serves to hold the train of wheels when wound upto prevent it running down until purposely released by a current fromthe exchange, as is. fully explained in turn hereinafter.

R C is a revolution-counting device, which may b e combined with thelatent switch when calls are paid for by meter. It may be of anywell-known construction as far as the actual counting mechanism isconcerned, but in order to adapt it to the switch I provide it with anexternal-toothed wheel 76 and the block- 17 with a crank-pin 77, so thatshould a call be eective the said pin, just when the said block reachesthe end of its stroke, will strike in the teeth of the wheel 76, andthus revolve the set of numbered disks ot the counter, and so registerthe number of calls made and act as a meter, which will always be insight, so that the calls may be checked as made. ,v

Instead of the contact-'plates being movable to expose the nu mber ofcontacts desired these plates may be xed and a movable insulator adaptedto move over them, so as to cover up a greater or less number of thecontacts employed, and thus leave exposed only as many as may berequired for the call.

The main or winding-up-lever serves to rotate the spindle 18 in onedirection, which winds up the block 17 or causes it to ascend or move inone direction, carrying with it the contact 30, which brushes across allthe contacts on the contact-plates which lie in its path at the moment.

The indicator-switch may be used in any position. When usedvertically,thenutblock 17 on the helical spindle 18, bearing theflexible contact spring or strip 30, will be raised by the hand-leversector-rack 25 engaging in the pinion 19, fast on the toothed wheel 20,which rotates the helical spindle and so raises the said nut, while inits downward motion it will fall by gravity. Should, however, it bedesirable to use the instrument in any other position-say horizontal-themovements of this nut-block in the unwindingdirection, it is obvious,might be effected by means of a spring or other source of power, whichis either wound up orextended when the nut is moved in the otherdirection by the windingup lever 25, and consequently the potentialenergy thereby stored in it will constitute the latent force necessaryto automatically return the block to its initial position when released.

31 is a spring-catch made to engage in a hole 32 in the back of the dial1/l,bearing the numerals or characters corresponding to the variousexchanges, dac., whenever the said hole in this dial is presented to thetooth on the end of the saidspring-catch 31. The object of this is fullydescribed under the heading Calling and operating.

The electromagnet 3 is normally deenergized-in fact, cut out ot' circuitaltogetherby the make-and-break contacts 32 33 and 34 35.

33 represents guide-arms on the blocks 17, which arms, cooperating withthe guide-bar 34, along which they travel when the said block is inmotion, serve to keep the block free from any lateral play.

The block 17 is preferably connected to earth, this connection beingindicated in the drawings by the earth-plate E. The contactplates 4, 5,6, 7, and 8 are connected with the line-wire L and the contacts l2, 52,62, 72, and 82 with the line-wire L2.

In Fig. 9 the connection of this switch with the printing apparatus,jack-switch, and special indicator at the exchange is shown.

Exchange printen- The exchange printer-that is, the printing apparatuswhich prints the name or its equivalent of the exchange or other specialoffice desired in a call and operated electrically by means of thelatent switch just above described-is shown in detail in Figs. 5and 8;also, its connections with the special jack-switch J S and the specialindicator S I, Figs. 6 and 7. This printer is a modification of anordinary printing or recording telegraph. It consists of anelectromagnet C M, hereinafter referred to as YOO IIO

the contact-magnet, electrically connected with the line-wire L andearthed at E2 through a battery P B, a type-wheel 35, bearing in typeletters, figures, words, or other characters or signs representing thevarious exchanges and other offices, if desirable, the types beingarranged around the periphery of the wheel and the number of themcorresponding with the number of contacts 4' on the exchangecontact-plate 4 of the latent switch. This typewheel is operatedautomatically by the coperatiou of the magnet 3, traveling contact 30,and the contacts 4 of the latent switch,in conjunction with electriccurrents emanating, preferably, from the battery P B, but notnecessarily from the exchange, the working being effected through themedium of the armature 36, pivoted at C', of the magnet C M, the ratchetescape-wheel 37, the pawl or detent 38, and the double tripping-lever43, the detailed actions of which will be described later on underCalling and operating. Another electromagnet P M, hereinafter referredto as the printing-magnet, is electrically connected with the line-wireL2 and governs an armature 40, pivoted at'O2, the tripping-lever 39,above mentioned, type-hammer 41, a pair of feed-rollers 42, and a detent43, which latter, in conjunction with the ratchet 45 on one of theserollers, turns the roller and advances the tape for spacing purposes byfriction with its surface. A lever 46, pivoted at O3 and bearing a tooth47, adapted to be brought into and out of engagement with the teeth ofthe escape-ratchet 37,will be described,as regards its functions, lateron. The supply of paper tape maybe carried, as usual, in the form of aroll upon a skeleton bobbin 48, mounted in a bracket, so as to be freetorevolve. I R are the inking-rollers. This printingr apparatus maybe atwill electrically connected with the line-wires, as above stated,through the mediuln of the special switch next described.

Oscillatory jack-switch.-This switch is a modication of the well-knownjack-and-plug type. The line-wi res L and L2 terminate in a plug J P,the wire L in the metallic sleeve of the plug, andthe wire L2 in themetallic tip of the plug,the tip and sleeve being of course electricallyinsulated one from the other. This plug J P shown is a modification ofthe ordinary one, having its lines leading in through a stem orarm 58,which projects out from about the center of the underneath side of theplug,

and at right angles thereto, the object being to prevent the wiresgetting broken by frequent bending, as they do when they are led in atthe rear end of the plug, because in the latter case the pushing intoand pulling the plug out of the jack or socket bends the wires inreverse directions, and this frequently repeated, as it necessarily isin busy exchanges, necessitates frequent renewal. It will be noticedthat with the design of plug shown in Fig. 6 the wires are always quiteclear of the rear end of the plug, so that this can be thrust inthejack, as usual, without fear of crushing the cord containing thewires between the hand and the rear end of the plug. Moreover, the rigidstem provides a firm grip with which to pull the plug out of the socketwith greater facility. The jack consists of the casing 59; but insteadof the bush 60, of insulating material, at the entrance of the jack forthe reception of the plug being stationary, as usual, it is piVoted atO4, so as to permit the plug when inserted to be tilted, so that its tippoints downward, as shown in dotted lines. Normally the plug J P restsin the jack in an oblique position, with its tip pointing downward. Aspring 6l, engaging in notches 62 in the oscillatory bush, is providedto hold the block in the position in which it is put. The free end ofsaid spring rests normallyin one or other of said notches and rides outof theml when the block is moved with slight force, but not by the mereweight of the plug. A set of spring-contacts 52 53 54 55 56 57 are fixedin an insulating-block 63, secured in the rear end of the casing 59. Thesprings 52 and 53 are shown electrically connected through the plug J Pwith the line Wires L and L2, respectively, and through connection wireswith the exchange printer, and When the plug 49 is inserted in the jackhorizontally, as shown in Fig. 6, these two springs make contact onewith the tip and the other with the sleeve of the plug, so that the saidprinter at the exchange is thereby thrown into circuit with thesubscribers latent switch when desired. The springs 54 and 56 areconnected through a generatoror battery E B to earth, (indicated by theplate E4.) These lare for the purpose of giving the engaged or busysignal to the calling -snbscriber when the called-subscrihers line isalready engaged,the indicator in question consisting of eithera specialmagnetic bell or an electric bell 76 and electromagnetic device 77, suchas shown in combination at E S, Fig. 9, and which is further described under Calling and operating. Normally the plug J P being in the inclinedposition makes contact by its tip with the spring-contact 55 and by thesleeve with the contact 57, slightly depressing these twocontact-springs, so that they break contact with the two springs 54 and56. Consequently when the said plug is either drawn out or lowered intothe horizontal position, the two springs 55 and 57 being therebyreleased spring up and make contact with the two springs 54 and 56, asshown in Fig. 6, and th us automatically actu ate the indicator when theline is engaged, as desired. The cont-actsprings 55 and 57 are inelectrical connection with the special indicator S I at the originatingboard and jack S B at the switching-board, these connections beingobvious from a glance at Figs. 6 and 7 or Fig. 9.

In Fig. 9 the two contact-springs 55 and 57 are shown in contact withtwo stud-contacts, these latter being merely substitutes for thecontact-springs 54 and 56 in Fig. 6.

Any one or more of the contactsprings IOO IIO

shown in the jack .l S, Fig. 6, 'may be replaced by contact-studs orother suitable forni of contact.

electrotnagnets 64 and 65, the one coil, 64,'

having one of its terminals normally in electrical connection with theline-wire L' and the one, 65,*one'of its terminals in connec-l tion withthe line-wire TP through the medium of the springs 55 and'57 ofthejackswitch J S, the plug 49 of which normally rests in the said jackin an oblique position, so that the tip 50 of the said plug is incontact with the spring 55 and sleeve 51 in contact with the spring 57,as shown'iu dotted lines. The other two terininals'of the coils inquestion are connected through a battery to earth, (indicated by theplate E5.) The poles of this electromagnetic device have their innersides, which face each other, preferably finished obliquely, as shown at66, and be-v tween these poles is hung or pivoted the armature 67 insuch manner that it can oscillate from the one side to the other. At theopposite end of this armature is a rigid cross-v bar, on each extremity`of which is fixed, at an angle thereto, a disk or plate 68 69, whichdisks advantageously diierin color or are otherwise rendered visiblydistinguishable: In front of the armature and supported centrallybetween the two magnets is a window 70, the whole being so arranged, aswill be seen, that attraction of the armature to one pole or the otherbrings [one of the disks or plates 66 or 69 on the ends ot' itscross-bar to appear at the window 70. This indicator and its functionsare further dealt with underv the heading Calling and operating, but itmay be here briefly mentioned that it serves to indicate at aglance'toan operator at the eX- change whether a call is for a subscriber on thatexchange or some other or distant one, and this is understood accordingto which disk 68 or 69 -is presented at the window 70 or otherpredetermined arrangement, as the case may be. Fig. 7 shows the armatureof this indicator in one of the positions it assumes the instant a callis made by means of the latent switch first-above described.

The numerical printer and its circuits.- 'lhe instrument or apparatuscalled the numerical printer and shown at N P, Fig. 12, is the devicefor automatically printing the subscribers numbers. It consists,accordingly, of a type-wheel 91, bearing, preferably arranged in acircle around its periphery, the numbers 1 to 9, a 0, and a dot or dashor other sign representing zero. .There are thus eleven signs in all,corresponding with the eleven contact-ridges 5', 6', 7, and S on each ofthe plates 5, 6, 7, and 8 of the latent switch shown in Fig. 1. Thistype-wheel is connected with a ratchet-and-pawl mechanism substantiallysimilar to that described abovev in connection with the exchangeprinter. VIt is also similarly connect-ed with electromagnetic devicesand provided with paper-tape roll and inking and spacingdevices and mayhe also fitted with-means for.l bringingy the wheel back to zero-eachtime 4after itV has printed a ligure, this latte'nhcontrivancev being tosave the type-wheel having tomake a complete revolution after printingeach figure of the called-su bscribers number. kvV' S V S are two visualor lightsignals'operated by current-s sent through relays C R C R. R3and Rfare resistances bridged across the line-Wires preferably at thepoints and in the manner shown in the iigure and 4serve to prevent theelectrical balance of the line being upset by the'earth connected at E7.Thesesignals V S light up at each operating-board simultaneously on theoperators plug being inserted in the jack L S B, and they remain alightuntil cutout of circuit when cutting in the numerical printer. They arealso subsequently lighted by earthing the current ou the linesautomaticallybythe weight of the receiver when placed on theswitch-hooks at vthe end of a conversation, and thus also serve asclearing signals to the operators.

The functioning of the above signals is also further described under.Calling and operating'farther on. Y

Calling and operatingl will now procee-dl to describe in detail a calland the operating thereof, For the purposes of this descriptionit willbe assumed that a subscriber,.whotn for convenience I will call A,wishes to speak with a subscriber B, vBs number being, say, 4105 on thelocal eX- change and this exchange indicated by the numeral 2 on theexchange-dial 4. A is therefore the calling-subscriber and B the calledsubscriber, and the call and operating thereof will be effected by thecombination of apparatus hereinbefore described, the subscribers latentswitch employed being of the gravity type, as in Fig. 11. To start thecall, A first sets the dials of thel latent switch to the exchange andnumber on that exchange assigned to B. This is done by merelyturning theknobs 12 in the outward direction, these actions advancing therespective contact-plates till they expose just the rightnumberVofcont-acts corresponding to the eX- change and numberdesired,and asthe exchange assumed in the present call is the lo'- calone and the numeral on the corresponding dial 14 denotes this exchange Asimply turns the said dial until the springpointer 16 drops into thenotch of the said dial immediately over the figure 2 on the face of thedial, thus advancing, as desired, the plate 4 through the medium of therackand-pinion device at the back and exposing two of its contacts 4 inthe path of the contact-brush 30 on the traveling block 17. A

next in like manner sets the numeral-dials 5, 6, 7, and 8, respectively,to 4, 1, 0, and 5, thus setting Bs number and TOO exposing in the pathof the contact-brush 30 corresponding numbers of contacts. Having donethis, A next winds up this switch by simply bringing around thehand-lever 25 by means of its handle as far as it will go toward theopposite side, this action, through themediutn of the toothed sector onthe said lever, the wheel 20, pinion 19, and teeth 18t'o11 the spindle18, rotating the latter, which thereupon carries up the nut-block 17,bearing the contact-brush 30.l The height to which this block will bethereby raised depends always upon whether the call is for a subscriberon the local exchange or some other exchange. For calls on the localexchange itis arranged so that they block will be arrested when it hasarrived about half-Way up in ordet that the contact 30 shall not actuatethe exchange printer at the exchange, because that is of courseunnecessary for a call 0n the local exchange, as the special indicator(see that heading) has in the meantime indicated it. It is only requiredwhen Bs number is on some other exchange to inform the operator at thelocal exchange what other exchange is required. This arresting of thecontact-block 17 is automatically brought about by the tooth on theupper end of the spring-catch 31 springing into the hole 32 in theexchange-dial as soon as the said hole is presented to it, which, asbefore explained, is arranged to ltake place whenever the dial is setfor local exchange. On the lower-or tail end of this spring-catch 31 isa projection 73, which is brought into the path of the traveling block17, or rather into the path of an insulated stud 74 on the said block,when the upper end of the springcatch 3l is in engagement with the hole32 in the exchange-dial'by reason of the said spring turning on itspivot 75, thereby tilting its tail end backward. Just as the blockarrives at the point at which it is arrested, as above explained, itdrops slightly and presses the contact 35 against the contact-stud 34,which is in electrical connection with the line-wire L, which in turn isin connect-ion with the special indicator S I (see Fig. 7) at theexchange through the plug J P and springs 55 and 57 in the specialjack-switch J S. The current waiting on the line is thereby earthed; butthe current is only a feeble one from the battery I B and not sufficientto energize the electromagnet 3, (see Fig. 1,) although this currentwill traverse this coil to earth; but the said current is sufficient foractuating the special indicator S I at. the exchange, which itdoesimmediately the traveling block makes the said contact. The normalposition of the armature of the indicator S I is central, as shown inFig. 9. The two line-wires L and L2 terminate in the jack-plug J P, theone L" in the sleeve 51 of the plug and the one L2 in the tip 50. Thisplug, as already explained, normally rests in the jack-switch J S in theinclined position, as indicated in dotted lines in Fig. 6, consequentlymaking contact with the springs 55 and 57, which close the circuit inwhich the indicator, Fig. 7, is included. rThis indicator S I havingbeen actuated, one of its disks (the one indicating local exchange) isthereby presented at the little window 70, as in Fig. 7, thus indicatingto the operator who iirst receives the call, and hereinafter referred toas the originatingr operator, that the call is fora number on thatexchange. The call 'having been thus announced, the operating iscommenced by the originating operatoratthecalling-board pulling the plugJ P out of tht-jack J S, thereby locking the subscribers switch bycutting ont all connection with the indicator S I. The contact-springs55 and 57 thereupon spring up and tnake contact with the twocontactsprings 54 and 56, respectively, which are connected through thebatteryEB to earth, (indicated by the eatt h-plate E4.) This is for thepurpose of giving the engaged or busy signal to any other callingsubscriber, automalical ly indicating to hitn that the line is engaged.This busy or engaged indicator preferably takes the form of abell-indicator, such as shown at E S, Fig. 9, "wherein itconsists of anordinary electric single-stroke bell 76 andan electromagnetic device 77,the armature 82 of the latter being pivoted at 78 and bears at one end aplate 79 bearing the wordEn gaged or similar information, this plateheing exposed at an aperture 80 in a board 81 in front whenever thearmature is attracted by the magnet. The bell 76 in it-s entirety mightobviously be dispensed with and in lieu thereof a simple gong might bemounted within reach of tite armature S2 to strike. The plug is theninserted in a jack of a local junction connection leading from thecallingboard to the switching-board, this action putting the visualsignals V S in circuit, and consequently lighting them. The operatorthere then plugs the jack leading to the numerical printer to ascertainthe num ber wanted. The numerical printer being now in circuit, thecurrent on the lineL,emanating from the battery P B, is strong enough toenergize the coil3, Figs. l, 9, and 13, attracting its armature, andthus releasing the catch 27 at the end of the lever out of the notch inthe wheel 20, and thus releasing the Winding-up mechanism. The block 17,carrying the contact 30, then commences its descent, breaking thecontact at 34 35, and consequently taking the earth Eoff the line, saidcontact brushing in succession those contact-ridges ot' the plates 5, 6,7, and Swhich lie in its path, and thereby giving a corresponding numberof pulsationsto the armature 36 of what [will call the contact-magnetC Mof the printerin question, thus rotating the type-wheel to the figure tobe printed, and on the contact 30 arriving in its descent at thecontact-studs 52, 62, 72, and 82 it earths at E', the current now comingfromv the battery N P B, which causes a pulsation of the armature 10 ofwhat I willcall the printing-magnet PM', thereby pressing theprinting-hammer and paper TIO against the type, and thus producingtheimprint. This action in detail is as follows: To the armature 36 ispivoted at 83 (see Fig. 5 for the details) a bent lever 39 and at 84 apawl 38, so that the said armature carries with it when attracted thisbent lever, the tip of which on coming in contact with the lfixed stop85 becomes depressed, thereby throwingr out its other leg, on whichthere is a pin 86, which latter pushes back the detent 43 oft the tipsof the pawl 38, and a lever 46, having a tooth 47, thereby releasing thesaid paw] and lever 46, both of-which being springpressed immediatelyengage in the teeth of the `ratchet escape-wheel 37. Each time thearmature drops it causes, by means of the pawl 38, av tooth -by-toothrotation of the ratchet, which in turn rotates vthe respectivetype-wheel 35, thesepulsations occurring for every contact on the plates5, 6, 7, and 8 brushed by the contact-spring 30, thus causing the propertype to be presented to the typehammer, and on the said contact-springarriving at each of the contact-studs 52 62 72 82 a pulsation is givenlo the armature 41 of the printing-magnet PM'. On this armaturebeingattracted by its magnet the printing-hammer 41 strikes the paper againstthe type-wheel, thereby printing on the paper the number, character, orsign which is presented at that kpoint of the type-wheel immediatelyabove the paper at the moment. Simultaneously the detent 43 is raised,and during the descent of the armature the detent 43 again catches onthe ends of the pawl 38 and toothed lever 46, bringing the former out ofthe teeth of the ratchet-escape 37 and the tooth on the lever 46 alsoout of engagement with the said escape-wheel, thus leaving the latterfree to be turned back to its zero or initial position under theinfluence of a coiled spring 105 within the barrel of the said wheel,which spring has ofcourse been wound up by the pawl 38 during thepulsations of the armature 36. When the armature drops, it also bringsdown with it the detent 43/, which,catching'in its descent in one ot'the teeth of the ratchet 45, fast on the friction-roller 42, rotatesthis roller, thus by friction rotating the other roller 42 and advancing the paper tape between them for spacing purposes after eachimprint. The nurnber being thus ascertained and printed for futurereference, the call is completed by connecting this number by taking theplug out ot' the jack 49 and putting it into the called-subscribers`jack S B'. The operator then depressesa key K, connected in thelines,which action causes a signal (bell'C B to ring to be given to bothsubscribers, indicating that the connection required is Icompleted.

The above is a description of the series of events or operations whichtake place to put one subscriber in connection with another on the localexchange. I will now proceed to describe what would take place had Bsnumber been on some other or distant exchange.

A would set his dials as before, except that the exchange-dial would ofcou rse beset to an i block 17 and obstruct its upward passage, asV

before, so that when the switch is wound up by the toothed sector-lever25 the block 17 will be thereby carried right to the top and press thespring 32 against the contact-stud 38, thereby earthing the latentcurrent onto the line L', the said current originating at the battery IB, thus actuating the special indicator, Fig. 7, at the exchange, asbefore. The operator at the calling-board new knowing .that the call isfor some distant exchange must ascertain which one, so instead ofpulling the subscribers plug J P out of the jack .I S simply brings itdown into the horizontal position (shown in full linesin Fig. 6,) thuscutting out of circuit the indicator S I and cutting in circuit theexchange-printer E P, Figs. 5 and 8, which thereupon prints the name ofthe exchange wanted. The contactsprings 55 and 57 being released ily upand make contact with two other springs 54 and `56, which are connectedthrough a generator or battery to earth, (indicated by the earth-VAplate E4.). This is for the purpose of. giving the engaged or busysignal, as previously explained. The mechanism and operation of theexchange-printer are almost identical with those oi" the numericalprinter and so needy not be here repeated, the difference consisting inthe type-wheel containing on its periphery words, numerals, characters,or other signs denoting exchanges, 85e., instead of the numerals for thenumbers, as in the other printer. Either or both of these printers maybe made simpler, it' desired, by eliminating the mechanism for returningthe type-wheel back to zero aft-er each print. The name of the distantexchange being thus ascertained, the originating operator plugs As linedirect into a jack corresponding to L S B, leading to theswitching-board of that exchange instead of, as in the former case, tothe switching-board at the same exchange, and the call is then completedb v the operator at this switching-board, as in the former case. Thuswithout any intercourse with the operators at the exchange the mostcoinplex telephonie service can be supplied by means ofthe combinationof apparatus above described.

Most of the apparat-us is of novel construction and specially adaptedone instrument to the other as well as to the whole system, to carry outthe invention in the best way, although in a fundamental form some ofthe instruments, I ain aware, are not novel for other' uses thantelephony.

The apparatus and system described in this specification have beendevised with the London system in view, so that certain modiications,which, however, are obvious, must IIO be made in some of the apparatusand also in the way they are grouped to adapt them to the service to besupplied. For instance, the exchange-printer herein described isconstructed to print the names or equivalents therefor of exchanges andother offices numbering fifty in all; but it is obvious that this numberis entirely dependent upon the number of exchanges, &c., and where thereare no junction exchanges the exchange-dial and contact-plates can bedispensed with entirely. As regards grouping, the combinations may bealso altered to suit the requirements and some of the instruments may beomitted entirely. For instance, the compound indicator might bedispensed with where there is only one exchange-that is, where there areno junction or distant exchanges as Well as the local one-and, again,other equivalent instruments maybe substituted for those eliminated. Forexample, instead of the subscriber-s latent switch being made to operatea printing device the latter may be eliminated and a revolution-counteror a counter-indicator substituted therefor, the said counterindicatorbeing operated by impulses imparted to a lever-armature in exactly thesame way as the printer is worked.

The end of a conversation is made known to the operators in the exchangeby the following means: 92 (see Fig. l) is an electromagnet normallydenergized, but supplied by a current when required from the exchange,so that the clearing-signal can be received there, said current beingderived from the batteries R O, indicating ring off.7 (Shown in Figs. 12and 17.) The armature 93 of this magnet is held normally out of orbeyond the magnetic field by means of the spring 94, but isautomatically brought into the ield when the hand telephone set 95 isplaced on the switch-hook arm by reason ofthe weight bearing down thesaid hook, which by its central stem 96 depresses the pivoted link f 97,causing the detent 98 on the latter to catch on the tip of the armature93 and pull it down. Immediately the armature is in the iield the spring94 makes contact with contact 100, which is earth-connected at E6,thereby earthing the current on the lines, which energizes the coil 92,and the armature 93 is drawn on to the magnet, in which position itmakes contact with the two contact-springs 99 and 100, thereby closingthe circuit, putting an earth on the line by reason of the spring 101and 102 being always in contact with the link 97, so that theclearing-signal can be received in the exchange, the spring 101 being inconnection with the line-Wire L' and the spring 102 in connection withthe linewire L2. This earthing of the current on the line causes thelamps V S in the exchange to light up, which serves as the clearing-ontsignal to the operators, and these lamps remain alight until theclearing is done.

Thus this invention consists of a group of apparatus for automaticallyelectrically signaling connections required from subscribers to thetelephone-exchange operators and from one exchange to another withouteither subscriber or operator speaking, thus securing secrecy ofmessages, as telephone instru ments form no part, necessarily, of theoperators apparatus, and they are therefore unable to tap or tamper withthe wires. The circuits are very materially simplified, and Amultipleswitchboards even for the largest exchanges are dispensed with, therebysaving enormous expense in construction and maintenance and doing awaywithnumberless sources of faults and wrong connections. With this systemit would be possible to carry on the operating with from twenty to fiftyper cent. of the stai required by the systems now in use. It isconsidered to be an improvement on the purely automatic systems, it isavailable for the largest as well as the smallest exchanges or groups,whereas the automatic systems will only work satisfactorilyup to alimited number, and the mechanism is necessarily too elaborate andcostly. In the case of multiple switchboards the cost per subscribersline increases as an exchange grows; but with this system the cost perline would always remain the same and the prime cost per line would bevery much less.

The novelty of the invention consists in part of the general arrangementor combination of the parts which in diierent forms have been used forother purposes, but not for telephony, and also some of the parts arenovel-such, for instance, as the apparatus or latent switch at the.subscribers endwhereby he can set his dials to the number required, andthe switch is worked preferably by currents from the exchange when theoperator is ready to operate the call.

What I claim, and desire to secure by Letters Patent, is y l.Asemi-automaticlatentsignaling-switch for actuating and controlling adistant indicator or signal, consisting of a frame in electricalconnection with one terminal of the circuit, lnovable contact-plates, acontact-piece on the, frame, an externally-screw-threaded spindlerotatably mounted in, but insulated from, the frame, means for rotatingthe spindle in one direction, a traveling nut-block mounted on saidspindle, and a contact carried by the nut-block in electrical connectionwith the other terminal of the circuit, and adapted to brush thecontacts on the plates and frame, substantially as described and shown.

2. The combination with an electric circuit and a distant indicator orsignal included in the circuit, of the semi-automatic latentsignaling-switch for actuating and controlling the said indicator orsignal, consisting of a frame in electrical connection with one terminalof the circuit, movable contact-plates, a contact-piece on the frame, anexternallyscrew-threaded spindle rotatably mounted in, but insulatedfrom said frame, means for ro- IOO IIO

tating the spindle in one direction, a traveling nut-block mounted onthe spindle, and a contact carried by the nut-block in electricalconnection with the other terminal of the circuit, and adapted to brushthe contacts on the plates and frame, substantially as described andshown.

3. The combination with an electric circuit and a distant indicator orsignal included in the circuit, and the semi-automatic latentsignaling-switch for actuating and controlling the said indicator orsignal, consisting of a frame in electrical connection with one terminalof circuit, movable contactplates, contacton frame, screw-spindlerotatably mounted in the frame, traveling contact-block on said spindlein electrical connection with other terminal of saidI circuit, of arevolutioncounter actuated by a projection on the said travelingcontact-block engaging on its downward travel in the driving-wheel ofthe counter substantially as described and shown.

4. The combination with an electric circuit a distant indicatoror'signal included in the circuit, and the semiautomatic latentsignaling-switch consisting of a frame in electrical connection with oneterminal of the circuit,

' contact on the frame, screw-threaded spindle rotatably mounted in, butinsulated from the frame, means for rotating the spindle, travelingnut-block, contact on said block in electrical connection with otherterminal of the circuit and adapted to brush the contact on the frame,of an electromagnetic printing device, a simple switch for cutting saidprinter in circuit and means for actuating said printer from thesemi-automatic latent switch, consisting of the adjustablecontact-plate, an electromagnet, the armature of which is adapted torelease the traveling contact which then falls by gravity lits contactbrushing the contacts on the adjustable plate thereby causing thepulsations of the printer, substantially as described and shown.

5. ln apparatus for use in connection with telephonic intercominunication, the combination with an electric circuit, of the latentswitch, the special compound indicator, the special jack-switch, theline-wires, the eX- change-printer having mechanism arranged and adaptedto return the type-wheel to zero or initial position after each print,and means for actuating, locking, and releasing the latent switch,substantially as described and set forth.

6. In apparatus for use in connection with telephonicintercommunication,the combination with an electric circuit, of thelatent switch, the special compound indicator, the special jack-switch,the line-wires, the eX- change -printer, and means for actuating,locking and releasing the latent switch,- substantially as described andset forth.

7. In apparatus for use in connection with telephonic intercommunicationthe combination with an electric circuit of the latent switch, thecompound indicator, the jackswitcli, the line-wires, theexchange-printer, having mechanism adapted to return the type-wheel toinitial position after each print, and means for actuating, locking andreleasing the latent switch, of the numerical printer, an oscillatoryjack-switch adapted to cnt said printer in and out of circuit with thecompound indicator and visual signals, all constructed, combined andoperating, substant-iallyas described and set forth.

The combination of apparatus constituting a complete semi-automaticsystem of telephonic intel-communication, comprising in combination withelectric circuits, telephone transmitter and receiver, indicator-bellengaged or busy device,the means for bringing the armature of theclearing-electromagnet into the magnetic field automatically by theweight of the transmitter and receiver when on the switch-hook, thelatent switch, the automatic revolution-counter, the linewires,theoscillatory jack-switch and plug, the compoundindicator,theeXchange-printer,the visual signal devices, the exchange-printer, thenumerical printer and intermediate jackswitch for connecting either withthe line, all; constrncted,combined and operating substantially asdescribed and set forth.

9. In a latent switch for use in connection with signaling telephonicconnections desired, the combination with the exchange-dial andtraveling contac'tblock, of a hole and spring-pressed catch adapted toengage in said hole when same is presented to it, a projection on thetail end of said catch adapted to project in the path of the travelingcontactblock automatically on the dial being set to a predeterminedpoint, substantially as described.

10. The apparatus whereby a signal is transmitted to a distance by theweight of the telephone hand set when placed on theswitchhoolgconsisting of the combination with the stem of theswitch-hook, of electromagnet the armature of same pivoted normally outof the magnetic field, a pivoted lever carrying a detent adapted toengage when lowered on the tip of the free end of the said armature andbring it into the magnetic field, two contacts constituting terminals ofthe electric j circuit in which is included an electrical signalingdevice, substantially as described and set forth.

11. An electric or magnetic printing apparatus the combination of thetypewhee1,. means for rotating same step by step, means for inking thetype, the magnetic or electromagnetic device,the armature,the ratchetand pawl for rotating the type-wheel the magnetic or electromagneticdevice and the printinghammer, the combination therewith of the springlocated in the type-Wheel and tending always to hold the wheel at normalposition,

IOO

IIO

TLO

the bent lever pivoted on the rotation-arm, the double detent pivoted onthe printing-zu'- mature adapted to en gage with the actuating- Iutestimony that I claim the foregoing as myiuvention I have signed myname in pres- I ence of two subscribing Witnesses.

ARTHUR THOMAS MILNOR THOMSON. Witnesses:

ROBT. A. BLAKE, FRED C. HARRIS.

